Composed element and corner connection applied herewith

ABSTRACT

Composed element, with at least two wood-based panel-shaped elements; wherein said panel-shaped elements can be coupled to each other at an angle and with a miter joint by means of a locking tongue and groove connection; wherein the tongue consists of a split tongue, with thus at least a first tongue portion and a second tongue portion, as well as a slit situated there between; characterized in that said slit, seen in cross-section, globally extends according to a direction which deviates from the direction of the center line of the panel-shaped element on which the tongue is provided.

BACKGROUND 1. Field of the Disclosure

This invention relates to a composed element consisting of at least twopanel-shaped elements, as well as to a corner connection appliedthereby.

In particular, the invention relates to a composed element, whichcomprises at least two panel-shaped elements, which are coupled to eachother or can be coupled to each other at an angle. Herein, the inventionrelates to any form of composed element which comprises at least twopanel-shaped elements, irrespective of the field of application. It isnoted that the composed elements does not have to consist exclusivelynor substantially of panel-shaped elements, however, that it sufficesthat the panel-shaped elements possibly only form a part thereof.

More particularly, the invention relates to panel-shaped elements, whichcan be coupled to each other by means of a locking tongue and grooveconnection, in particular by moving the panel-shaped elements laterallytowards each other and by coupling them by means of a turning movementand/or snap movement to each other at an angle. Moving the panel-shapedelements laterally towards each other means that these panel-shapedelements are presented sideways to each other with their respectivepanel edges.

Primarily, the present invention is intended for being applied in thefurniture sector, wherein the composed element consists of a piece offurniture or of a furniture component. More particularly, the presentinvention can be applied for composing loose furniture as well asbuilt-in furniture, such as, for example, kitchen furniture, dressingfurniture and the like, as well as for furniture components, such asdrawers. The invention is in particular suitable for being applied withfurniture which is sold in dismantled condition and has to be assembledand/or installed by the buyer or possibly by an installer. This type offurniture is also known under the denomination flat pack furniture or asRTA furniture. Herein, RTA stands for “Ready To Assemble”. It is notedthat the present invention can also be used in any other application,such as, for example, for wall panels, storage boxes, coffins and thelike.

More particularly, the invention aims at a composed element, such asexplained herein above, and a corner connection between panel-shapedelements applied hereby, which can be assembled and realized in a simpleand smooth manner.

2. Related Art

More particularly, the invention relates to a composed element of thetype which comprises two or more panel-shaped elements, which eachpossess coupling parts in the form of a tongue and a groove,respectively, wherein these coupling parts allow that the panel-shapedelements can be coupled to each other in a locking manner and at anangle. In this context, this is referred to as a mechanically lockingcoupling system, more particularly a locking tongue and grooveconnection. Further, this locking tongue and groove preferably arepresent in the form of a profile respectively extending in thelongitudinal direction of the panel-shaped element. A composed elementwhich makes use of such tongue and groove connection is known, amongstothers, from WO 2010/070605.

Substantially, there are two types of corner connections. A first typeof corner connection, in this context described as a common cornerconnection, relates to a connection wherein, in the longitudinaldirection of the formed corner, the panel edge of one of the twopanel-shaped elements coupled at an angle remains completely visibleafter they have been brought into the coupled condition. A second typeof corner connection relates to a connection wherein the panel-shapedelements are brought together in miter at their respective panel edge.In this case, this is also called a miter coupling or a mitered cornerconnection. Herein, the panel edges of the two panel-shaped elements inthe longitudinal direction of the formed corner are not visible orvisible in a limited manner only, when they were brought into coupledcondition. In certain applications, it is more desirable to work with amiter coupling instead of a common corner connection, for estheticalreasons.

In the field of esthetics, a miter coupling has some importantadvantages in respect to a common corner connection. By working with amiter coupling, a more solid impression is obtained. Further, this alsogives an impression of handcraft or at least of a more precise finishingof the composed element. Technically seen, by making use of a mitercoupling, it is avoided or restricted that the panels have to be maskedalong the side of the miter coupling by means of a relatively widemasking strip, such as, for example, a laminate strip or a masking stripof synthetic material, for example, an ABS strip(Acrylonitrile-butadiene-styrene). By means of a miter coupling, the useof the masking strip can be avoided, or a narrower masking strip can beused.

From WO 2010/070605, couplings are known for common corner connectionsas well as for mitered corner connections. WO 2010/070605 shows aprofile for a mitered coupling in FIG. 66.

The present invention aims at an improvement of, or an alternative for,the already known profile for mitered coupling from WO 2010/070605,wherein the coupling system preferably is improved in the field ofstability and strength of the composed element, as well as in the fieldof ease of installation, more particularly of the joining together ofthe component panels.

In fact, it is clear that such couplings, during assembly or coupling aswell as afterwards, are subjected to forces. These forces originate fromthe own weight of the composed element, as well as from possibleexternal loads to which the composed element is subjected. Consideringthat the profiles, however, mostly have to be realized in relativelythin panels, and moreover typically, however, not exclusively, are madein particle board, which, as known, can be relatively brittle, it isimportant to perform an innovating optimization on the applied profiles.

SUMMARY

The present invention thus primarily aims at possibilities foroptimizing such miter couplings.

To this aim, the present invention, according to a first independentaspect, relates to a composed element, which comprises at least twopanel-shaped elements, each with respective panel surfaces, wherein foreach panel-shaped element a center line is defined centrally between thetwo panel surfaces of that panel-shaped element; wherein saidpanel-shaped elements are manufactured of wood-based material; whereinsaid panel-shaped elements can be coupled to each other at an angle bymeans of a locking tongue and groove connection and hereby respectivelyform an inner and outer corner, wherein the inner and outer cornerdefine a theoretical miter line; wherein said locking tongue and grooveconnection respectively is substantially formed of a tongue on one ofsaid panel-shaped elements, of a groove on another of said panel-shapedelements and of locking elements provided on said tongue and groove;wherein, seen in cross-section, the panel surface of each panel-shapedelement at the side of said outer corner extends at least to the centerline of the panel-shaped element to which it is coupled; wherein thetongue consists of a split tongue, with thus at least a first tongueportion and a second tongue portion, as well as a slit situated therebetween; with the characteristic that said slit, seen in cross-section,globally extends according to a direction which deviates from thedirection of the center line of the panel-shaped element on which thetongue is provided. By making use of a slit which, seen incross-section, extends according to a direction which deviates inrespect to said center line, in other words, a slit which extends at anangle in respect to said center line, the locking tongue and grooveconnection can be optimized in the field of the strength of the lockingbetween two panel-shaped elements in coupled condition, on the one hand,and in the field of the force necessary for bringing two panel-shapedelements in coupled condition according to a certain direction, on theother hand. A suitable orientation of the slit provides for anorientation of the flexibility of the tongue adapted to the manner ofassembly. By applying such slit, a freedom of design is createdaccording to which the coupling can be optimized for any type ofapplication, such by suitably configuring and dimensioning the slit.

The locking elements provided on the tongue and groove provide for thatin a usual mutually coupled condition, the moving apart of therespective panel-shaped elements is counteracted. More particularly, themoving apart with a translation movement at least according to adirection of the center lines of the respective panel-shaped elementsand according to a direction perpendicular to the theoretical miter lineis counteracted by these locking elements.

According to a preferred characteristic of the first aspect of theinvention, said slit in the tongue, towards the open end, is directedinclined towards the respective panel surface situated on the innercorner of the aimed-at miter coupling. Herein, the axis line through theslit in the tongue encloses an angle which is larger than 0° and smallerthan 90° and preferably is smaller than the miter angle with the centerline of the panel-shaped element having the tongue. Herein, the miterangle is the angle which is enclosed by the center line of thepanel-shaped element having the tongue and the theoretical miter line ofthe miter coupling. By directing the slit in the tongue, as describedherein above, inclined towards the panel surface at the side of theinner corner, it is obtained that the orientation of the flexibility ofthe tongue is adapted to the manner in which the panels are coupled.

It is clear that the tongue, too, globally seen, preferably extendsinclined towards the respective panel surface which is situated at theinner corner.

According to another preferred characteristic of the first aspect, thetongue is situated eccentric in respect to the midpoint of thetheoretical miter line, such preferably in the direction of said innercorner. Due to the eccentric arrangement of the tongue, more materialcan be kept on the outer corner, which leads to a sturdier constructionand therefore a diminished risk of a breaking-off of material portions.In the case of a panel-shaped element with a covering, such as, forexample, a laminate covering, an eccentric arrangement may contribute toa better resistance against warping of the panel-shaped element at thelocation of the outer corner as a result of tensile stress in thecovering, such that the risk of a poor connection of the panel-shapedelements on the location of the outer corner can be restricted. Tensilestresses in the covering, in the example of a laminate covering, canoccur under the influence of temperature and temperature differencesduring and after the production process. Hardening the resin present inthe laminate, for example, is accompanied by a shrinkage which is largerthan the possible deformation of the underlying material of the basicboard of the panel-shaped elements. Further, an eccentric arrangement ofthe tongue allows obtaining, during assembly, an improved turningmovement of the tongue in the groove.

According to a further preferred characteristic of the first aspect ofthe present invention, said tongue is cut free on at least one side,preferably by means of a cut, more particularly by means of a narrowincision. By a narrow incision, an incision is meant having a depthwhich is larger than the width. By cutting the tongue free on at leastone side, the tongue or the adjacent tongue portion can be rendered moreelastic. This latter allows optimizing the coupling even further bymaking a compromise between the strength of the locking between twopanel-shaped elements in coupled condition, on the one hand, and theforce required to bring two panel-shaped elements in coupled condition,on the other hand.

Still more particularly according to the first aspect of the invention,it is preferred that the tongue is cut free on one side only, preferablyon the side of the tongue situated closest to the formed outer corner.By cutting the tongue free on one side only, it is prevented that thetongue would be too sensitive and becomes less resistant againstbreaking-off. The preference of cutting a tongue free on the sidesituated closest to the formed outer corner is primarily important whenthis characteristic is combined with an eccentric tongue, wherein thetongue is situated closer to the inner corner than to the outer corner.

According to a preferred embodiment of the first aspect of theinvention, the aforementioned locking elements are present at the heightof one side of the tongue only, whereby at the other side of the tongue,this latter is free from locking elements. This characteristic allowsthat the panel-shaped element having the tongue can be turned into thecorresponding panel-shaped element having the groove in a beneficialmanner, or in other words the respective panel-shaped elements can beturned into each other. According to a particular deviating embodiment,in fact locking elements can be present at the height of the other sideof the tongue, however, these last-mentioned locking elements are lesspronounced than the locking elements situated at the height of the firstside of the tongue.

According to another preferred characteristic of the first aspect of theinvention, said groove, on at least one side thereof, seen incross-section, is bordered by a lip extending to beyond said theoreticalmiter line, seen from the panel-shaped element having the groove, whichlip is called a protruding lip herein below. This aspect of theinvention offers the advantage that a contact surface can be formedbetween the tongue and the groove beyond the theoretical miter line. Incoupled condition, such contact surface can provide for an improvedsupport of the tongue and in this way contribute to an improved lockingof the panel-shaped elements. In this case, as well as in the hereinbelow described applications, the term “contact surface” has to beinterpreted in its broadest sense as a zone where a contact can takeplace, wherein such zone, seen in cross-section, can extend over adistance as well as can consist of a local contact point.

Herein, it is preferred that said protruding lip is located at the sidewhich is situated closest to the formed outer corner. Further, at theheight of this protruding lip at least one contact surface shall beformed between the tongue and the groove. In coupled condition of thepanel-shaped elements, this contact surface will provide for a supportof the tongue which is effective at least according to the directionperpendicular to the center line of said panel-shaped element having thetongue.

According to still another preferred characteristic of the first aspectof the invention, said protruding lip in coupled condition forms twocontact surfaces with the tongue which provide for a support which iseffective at least according to the direction perpendicular to thecenter line of said panel-shaped element with said tongue.

According to the first aspect of the invention, it is preferred that atleast one of said contact surfaces is situated beyond the theoreticalmiter line at the side of the panel-shaped element having the tongue.This aspect of the invention offers the advantage of offering additionalstrength to the formed mitered corner connection.

It is clear that in respect to the first aspect of the presentinvention, the preceding characteristics do not exclude that also on theother side of the groove, which is situated closest to the formed innercorner, a protruding lip can be present.

More particularly, in respect to the first aspect of the invention, itis of interest to provide, at the side of the groove which is situatedclosest to the formed inner corner, a smaller protruding lip portion,wherein the panel surface of the panel-shaped element having the groovecontinues at the height of the inner corner beyond the theoretical miterline, seen from the panel-shaped element having the groove, as a resultof which at that location a contact surface is formed which coincideswith a portion of said panel surface.

According to a second independent aspect, the invention relates to acomposed element, which comprises at least two panel-shaped elements,each with respective panel surfaces, wherein for each panel-shapedelement a center line is defined centrally between the two panelsurfaces of that panel-shaped element; wherein said panel-shapedelements are manufactured of wood-based material; wherein saidpanel-shaped elements can be coupled to each other at an angle by meansof a locking tongue and groove connection and hereby form an inner andouter corner, wherein the inner and outer corner define a theoreticalmiter line; wherein said locking tongue and groove connectionrespectively is formed substantially of a tongue on one of saidpanel-shaped elements, of a groove on another of said panel-shapedelements and of locking elements provided on said tongue and groove;wherein, seen in cross-section, the panel surface of each panel-shapedelement on the side of said outer corner extends at least to the centerline of the panel-shaped element to which it is coupled; with thecharacteristic that said groove, on at least one side thereof, seen incross-section, is bordered by a lip which extends to beyond saidtheoretical miter line. Said lip is also called protruding lip. Thisaspect of the invention offers the advantage that a more robustembodiment is obtained and/or that particular contact surfaces can beformed between the panel-shaped elements to be coupled. Moreparticularly, by applying a protruding lip, a contact surface can beformed between the tongue and the groove beyond said theoretical miterline, seen from the panel-shaped element having the groove. In coupledcondition, such contact surface can provide for an improved support ofthe tongue and in this manner contribute to an improved locking of thepanel-shaped elements.

According to a preferred characteristic of the second aspect of theinvention, said protruding lip preferably is situated at the side of thegroove which is situated closest to the formed outer corner. Further, atthe height of this protruding lip at least one contact surface is formedbetween the tongue and the groove. In coupled condition, this contactsurface can provide for a support of the tongue which is effective atleast according to the direction perpendicular to the center line ofsaid panel-shaped element having the tongue.

According to another preferred characteristic of the second aspect ofthe invention, said protruding lip, in coupled condition, forms twocontact surfaces with the tongue, which provides for a support which iseffective at least according to the direction perpendicular to thecenter line of said panel-shaped element having the tongue.

According to still another preferred characteristic of the second aspectof the invention, it is preferred that at least one of said contactsurfaces is situated beyond the theoretical miter line at the side ofthe panel-shaped element having the tongue. This characteristic offersthe advantage of offering additional strength to the formed miteredcorner connection.

It is clear that also in respect to the second aspect of the presentinvention, the aforementioned characteristics do not exclude that onboth sides of the groove a lip can be present which extends to beyondsaid theoretical miter line.

More particularly, it is also in respect to the second aspect of theinvention of interest to provide, at the side of the groove situatedclosest to the formed inner corner, a smaller lip, which extends tobeyond the theoretical miter line, wherein the panel surface of thepanel-shaped element having the groove continues at the height of theinner corner beyond the theoretical miter line, as a result of which atthat location a contact surface is formed, which coincides with aportion of said panel surface.

According to a third independent aspect, the invention relates to acomposed element, which comprises at least two panel-shaped elements,each with respective panel surfaces, wherein for each panel-shapedelement a center line is defined centrally between the two panelsurfaces of that panel-shaped element; wherein said panel-shapedelements are manufactured of wood-based material; wherein saidpanel-shaped elements can be coupled to each other at an angle by meansof a locking tongue and groove connection and hereby form an inner andouter corner, wherein the inner and outer corner define a theoreticalmiter line; wherein said locking tongue and groove connectionrespectively is formed substantially of a tongue on one of saidpanel-shaped elements, of a groove on another of said panel-shapedelements and of locking elements provided on said tongue and groove;wherein, seen in cross-section, the panel surface of each panel-shapedelement at the side of the formed outer corner extends at least to thecenter line of the panel-shaped element to which it is coupled; with thecharacteristic that said tongue is cut free on at least one side,preferably by means of an incision, more particularly by means of anarrow incision. By cut free is meant freed from still presentsurrounding material of the respective panel-shaped element. By a narrowincision, an incision is meant having a depth which is larger than thewidth. By cutting the tongue free on at least one side, the tongue orthe adjacent tongue portion can be rendered more elastic. This latterallows optimizing the coupling even further in the field of the strengthof the locking between two panel-shaped elements in coupled condition,on the one hand, and force required for bringing two panel-shapedelements into coupled condition, on the other hand.

Still more particularly according to the third aspect of the invention,it is preferred that the tongue is cut free on one side only, preferablyon the side of the tongue situated closest to the formed outer corner.By cutting the tongue free on one side only, it is prevented that thetongue would be too sensitive and less resistant against breaking-off.The preference of cutting a tongue free on the side situated closest tothe formed outer corner is primarily important when this characteristicis combined with an eccentric tongue, wherein the tongue is situatedcloser to the inner corner.

It is noted that all aforementioned aspects of the invention can becombined at choice, inasmuch as they do not show any contradictorycharacteristics. Also, all subordinate characteristics, which aredescribed by means of the first, second and third aspect, can becombined therewith, this inasmuch as such combinations do not result incontradictory characteristics.

Below, some preferred additional characteristics of the presentinvention will be listed, which can be applied in combination with anyof the preceding described aspects of the invention or of theabove-mentioned combinations of aspects and/or subordinatecharacteristics.

According to an important preferred characteristic, the tongue and thegroove have such a profile that they can be brought in a mutuallycoupled condition by means of a turning movement as well as atranslation movement towards each other. This characteristic offers theadvantage that assembling or constructing the composed element can beperformed in a smooth and/or simple manner.

According to another preferred characteristic, the tongue and groovehave such a profile that they can be brought into a mutually coupledcondition by means of a translation movement according to a directionwhich is directed inclined in respect to the center line and preferablyaccording to the direction of the slit of the tongue or according to adirection transverse, perpendicular or approximately perpendicular tothe theoretical miter line. This characteristic offers the advantagethat the flexibility of the tongue is adapted to the manner in which thecomposing panel-shaped elements are brought together during theassembly.

According to another preferred characteristic, the tongue and groovehave such a profile that the panel-shaped elements can be brought in astable intermediate position which differs from the final coupledcondition. This stable intermediate position corresponds to a first easylocking, by which the panel-shaped elements during assembly remaincoupled when released. Possibly, the panel-shaped elements can easily beloosened again starting from this intermediate position. Of course,starting from this intermediate position the panel-shaped elements canbe locked further and brought in the final coupled condition.

According to a further preferred embodiment, the tongue and/or thegroove are formed by profiles which are provided in the panel-shapedelements themselves, and preferably they are realized in one piece inthe respective panel-shaped element, for example, by means of a cuttingtreatment and/or machining treatment, such as a milling treatment. Thisoffers the advantage that no separate elements are necessary forconnecting the panel-shaped elements at an angle. Another advantagethereof consists in that such profiles can be milled into thepanel-shaped elements in a simple manner and a continuous locking tongueand groove connection can be realized smoothly along the entire cornerconnection.

Preferably, the tongue and/or groove are formed of the material of thebasic board with which the panel-shaped element is formed. This offersan important advantage for the manner of production of the panel-shapedelements of the composed element.

However, this does not exclude that according to a particular embodimentthe locking tongue and groove connection can make use of a contactsurface formed by an insert and/or of a locking element which isrealized as an insert, wherein said insert respectively is provided inan edge of one of the panel-shaped elements. More specifically, suchinsert may consist of a strip which is movable or is provided of amovable part with a contact surface or locking portion which cancooperate with a tongue or groove formed on the other panel-shapedelement, a locking element formed on the other panel-shaped element,respectively.

According to a possible embodiment, the tongue and the groove havelocking elements at the height of the two sides of the tongue. However,according to a further preferred embodiment of the present invention,the locking elements, at the height of the side of the tongue which islocated closest to the formed outer corner, are less pronounced than thelocking elements at the height of the tongue which is located closest tothe inner corner.

According to another preferred embodiment, the composed elementcomprises the characteristic that the panel-shaped elements comprise oneor more incisions, such as said slit in the tongue or such as saidincision at one side of the tongue, wherein at least one of theaforementioned incisions is partially or entirely filled with anelastically deformable material. This characteristic of the presentinvention can contribute to an elasticity of the tongue or of theindividual tongue portions, which elasticity is adapted to theapplication and to the final embodiment. Also, providing an elasticallydeformable material or a filler can contribute to an improved resistanceof the panel-shaped elements against damage; more particularly animproved resistance against damage of the tongue profiles.

According to a possible preferred embodiment, the composed element showsthe characteristic that the panel surface of each panel-shaped element,seen in cross-section, at the side of the formed outer corner, extendsup to a small distance from said outer corner, more particularly adistance smaller than ¼ of the panel thickness of the panel-shapedelement to which it is coupled, still better up to a distance smallerthan ⅙ of the panel thickness of the panel-shaped element to which it iscoupled. This characteristic has the advantage that the panel-shapedelements can come together at the outer corner according to a closingplane which possibly deviates from the theoretical miter line of theformed miter coupling. This allows achieving a better protection of thetongue profile. According to a possible embodiment, said panel surfaceextends right up to said outer corner.

According to a possible preferred embodiment, the composed element showsthe characteristic that it can receive a separately applied cornerelement at the height of one or more of said formed inner or outercorners. This characteristic allows giving an appropriate appearance tothe composed element by working with separate corner elements, whichhave an appropriate appearance and/or possibly have improved mechanicalfeatures. The separately applied corner element can have a roundedshape, as a result of which the composed element adopts a rounded shapeat the height of the inner and/or outer corner. The composed element mayalso obtain improved mechanical features at the height of the innerand/or outer corner by working with separately applied corner elementsof an appropriate material, such as, for example, metal or syntheticmaterial, more in particular, for example, a corner elementsubstantially manufactured of rubber or stainless steel or any otherappropriate material.

According to a possible preferred embodiment, the composed element showsthe characteristic that the panel surface of the panel-shaped elementhaving a groove on the side of the formed inner corner continues at theheight of this inner corner to beyond the theoretical miter line, as aresult of which a contact surface is formed at this place, whichcoincides with a portion of said panel surface. This characteristic hasthe advantage that hereby the assembly of the panel-shaped elements canbe simplified further, for example, in that this contact surface forms asupport surface during the turning-in of the panel-shaped element havingthe tongue.

According to a deviating embodiment, the composed element shows thecharacteristic that the panel surface of each panel-shaped element onthe side of the formed outer corner, seen in cross-section, instead ofextending at least to the center line of the panel-shaped element towhich it is coupled, extends up to a distance from said outer cornerwhich is smaller than ¾ of the panel thickness of the panel-shapedelement to which it is coupled.

It is noted that in the case that a slit in the tongue is applied, thelocation, width, depth and orientation of this slit form degrees offreedom in the design of a composed elements and the corner connectionsapplied therewith according to one or more aspects of the presentinvention. The location, and to a certain extent the orientation, too,determine the thickness ratio between the two tongue portions formed inthis manner. To this aim, the thickness of the tongue portions can bedetermined at the height of the theoretical miter line. This ratio canbe chosen as a design parameter for the applied corner connectionsaccording to one or more aspects of the present invention and can beoptimized in function of the type of load which is expected for eachpanel-shaped element of the composed element. The thickness of eachtongue portion in fact determines the flexibility of the respectivetongue portion, whereas each tongue portion contributes to differentcomponents of the locking forces of the locking tongue and grooveconnection.

The width, depth and orientation of the slit in the tongue substantiallydetermine the flexibility of the two tongue portions. These threeparameters can be applied for searching, per selected basic material ofwhich the panel-shaped elements are composed, an optimum between thestrength of the locking between two panel-shaped elements in coupledcondition, on the one hand, and force required for bringing twopanel-shaped elements into coupled condition. In other words, acompromise between ease of installation and stability of the finallyformed composed element.

Further, it is also noted that in the case that the tongue is cut free,the width, depth and orientation of the incision on the exterior of thetongue substantially determine the flexibility of the tongue or adjacenttongue portion. These three parameters can be applied again forsearching, per chosen basic material of which the panel-shaped elementsare composed, an optimum between the strength of the locking, on the onehand, and the force required for bringing two elements into coupledcondition.

According to a particular embodiment, the invention relates to acomposed element according to any of the preceding aspects, wherein saidgroove, seen in cross-section, is bordered on at least one side thereofby a lip which, at least with a portion thereof, is located beyond saidtheoretical miter line, and wherein this lip in coupled condition islocated at the side of the tongue situated closest to the formed outercorner, with the further characteristic that said portion provides atleast a contact surface for the tongue. In this manner, a robustcoupling is obtained. According to possibilities subordinate thereto,which may or may not be combined with each other, the composed elementfurther is characterized:

-   -   in that the lip has a distal end which extends up to the plane        of the panel-shaped element in which the groove is provided and        which is situated on the inner corner and preferably is formed        by a portion of the inner wall of the panel-shaped element;    -   in that the panel which is provided with the tongue comprises a        protruding edge portion which, at the exterior, provides for a        prolongation of the panel surface and which is situated, at the        inner side, opposite to said portion of the lip and preferably        adjoining thereto, wherein this protruding edge portion extends        at least up to the center line of the panel-shaped element which        comprises the groove, and preferably up to the actual outer        corner.

According to a particular embodiment of the last-mentioned of said twopossibilities, the protruding edge portion, in the proximity of itsdistal end, comprises a locking part, which in coupled condition engagesbehind the other panel-shaped element, by which is prevented that thisedge portion can deform, for example, can warp after a certain time.

According to a particular embodiment, the invention relates to acomposed element according to any of the aforementioned aspects, whereinthe tongue consists of a split tongue, with a slit, which, seen incross-section, globally extends according to a direction which deviatesfrom the direction of the center line of the panel-shaped element onwhich the tongue is provided, with the further characteristic that theslit, globally seen and/or with the wall thereof situated closest to theinner corner, extends from the free end thereof towards the bottominclined towards the panel surface which is located at the inner corner.

According to a fourth independent aspect, the invention relates to acomposed element, which comprises at least two panel-shaped elements,each with respective panel surfaces, wherein for each panel-shapedelement a center line is defined centrally between the two panelsurfaces of that panel-shaped element;

-   -   wherein said panel-shaped elements preferably are manufactured        of wood-based material;    -   wherein said panel-shaped elements can be coupled to each other        at an angle of 90 degrees or approximately 90 degrees by means        of a locking tongue and groove connection and herein        respectively form an inner and outer corner, wherein the inner        and outer corner define a theoretical miter line;    -   wherein said locking tongue and groove connection substantially        is formed of a tongue on one of said panel-shaped elements, of a        groove on another of said panel-shaped elements and of locking        elements provided on said tongue and groove, respectively;    -   wherein, seen in cross-section, the panel surface of each        panel-shaped element at the side of the formed outer corner        extends at least up to the center line of the panel-shaped        element to which it is coupled;    -   wherein the tongue preferably consists of a split tongue, with        thus at least a first tongue portion and a second tongue        portion, as well as a slit situated there between;        with the further characteristic that said tongue, at the        location of the theoretical miter line, is located entirely        outward of the midpoint of the theoretical miter line, such        between the midpoint and the inner corner. According to this        aspect, a connection is obtained which can be smoothly turned        into each other and wherein the material of the panel-shaped        elements is situated relatively far from the coupling parts, as        a result of which possible deformations, which may occur during        the joining together at the height of the coupling parts, do not        have any influence on the material at the outer corner.

According to a fifth independent aspect, the invention relates to acomposed element or collection of composed elements, wherein eachcomposed element comprises at least two panel-shaped elements, each withrespective panel surfaces;

-   -   wherein said panel-shaped elements preferably are manufactured        of wood-based material;    -   wherein said panel-shaped elements can be coupled to each other        at an angle by means of a locking tongue and groove connection        and thus form a corner connection;    -   wherein said locking tongue and groove connection substantially        is formed of a tongue on one of said panel-shaped elements, of a        groove on another of said panel-shaped elements and of locking        elements provided on said tongue and groove, respectively;        with the further characteristic that in such composed element as        such, or in a collection of such composed elements, at least two        of such corner connections are present, however, wherein at the        one corner connection panel-shaped elements are applied of which        at least one panel-shaped element has a panel thickness which        differs from the panel thicknesses of the other corner        connection; and that on both corner connections a tongue and        groove connection is applied, which are realized by means of        tongue and groove profiles which, in respect to at least the        tongue profile and/or the groove profile, are identical to each        other. By a “collection”, herein primarily a furniture        collection has to be understood, thus, furniture which are        intended to belong together, or a furniture collection, for        example, RTA furniture collection, from which different pieces        of furniture can be constructed. By using tongue and groove        profiles which are identical, irrespective of the differences in        panel thickness, the advantage is obtained that at least for        these profiles use can be made of the same cutting tools, for        example, milling cutters. The edge portions which are located        outside of the tongue and groove profiles are of a simpler form        and possibly are easier to adapt to the different panel        thicknesses. Depending on the design of these edge portions,        these mutually possibly can also be realized by means of the        same profiling tools.

It is clear that the fifth aspect can be applied with miteredconnections as well as with other corner connections.

It is noted that all embodiments of the first to the fifth aspect can becombined at choice, inasmuch as such combination does not comprise anycontradictory characteristics. Also, each aspect can be combined withcharacteristics as such which are described as subordinate to anotheraspect, this also according to all possible combinations, inasmuch assuch combinations do not comprise any contradictory characteristics.

As becomes clear from the aspects described herein above, the inventionin most cases relates to composed elements which comprise at least twopanel-shaped elements, which are manufactured of wood-based material.However, it is not excluded to apply, according to a deviating variant,the corner connection of the invention in combination with panel-shapedelements which consist of other materials, at least inasmuch as thepanel-shaped elements then consist of materials which are suitableand/or typical for being applied in furniture.

The invention shows its advantages best when the material shows one ormore of the following characteristics:

-   -   the panel-shaped elements substantially consist of a basic board        formed of solid wood;    -   the panel-shaped elements substantially consist of a basic board        formed of a wood-based pressed board, in particular a MDF, HDF        or particle board;    -   the panel-shaped elements are formed of melaminated board;    -   the panel-shaped elements are formed of multi-layered and/or        multi-part board;    -   the panel-shaped elements comprise a lightweight board, possibly        with edges from another material, wherein such lightweight board        consists, for example, of a particle board which is at least        partially composed of flax chips and/or which comprises        lightweight particles, such as expanded synthetic material        particles;    -   the panel-shaped elements are constructed as a hollow board or        as a board provided with cavities, for example, with a honeycomb        core, possibly with edges from another material; the        panel-shaped elements are constructed of a basic board with a        covering, more particularly a covering of synthetic material or        textile.

By multi-layered material a panel-shaped element or panel is intendedwhich is composed of a plurality of thin layers of a same or similarmaterial, such as plywood board, as well as a panel which is composed ofa plurality of structural layers, which are formed of a clearlydifferent material, such as, amongst others, sandwich panels.

It is clear that the panel-shaped elements according to the presentinvention, on the edges extending transverse to the longitudinaldirection of the locking tongue and groove connection, can be providedwith a masking strip, for example, a laminate strip or a masking stripof synthetic material, for example, an ABS strip. Hereby, the ends ofthe tongues and grooves in coupled condition can be hidden from view. Inthe case of the miter coupling according to the present invention, themasking strip can also be cut off with a miter. The cut of the maskingstrip then will not coincide with the contour of the profiles. Suchmasking is performed at the factory.

The corner connection according to the invention can be performed,wherein, seen in cross-section, the locking tongue and groove connectionshows overlapping contours. Hereby, a so-called clamping tension can beobtained. Hereby, the panels-shaped elements, in their mounted finalposition, can be connected to each other with a so-called pretension.Herein, the panel-shaped elements come into mutual contact on one ormore places. These places are also called contact surfaces. By applyingsaid overlapping contours, it can be provided for that the panel-shapedelements are drawn towards each other with a permanent tension at theheight of these contact surfaces.

Further characteristics of the invention will become evident from thedetailed description and claims following below.

BRIEF DESCRIPTION OF THE DRAWINGS

With the intention of better showing the characteristics of theinvention, hereafter, as an example without any limitative character,some preferred embodiments are described, with reference to theaccompanying drawings, wherein:

FIG. 1 in perspective represents a composed element according to theinvention;

FIG. 2 only represents two panel-shaped elements, connected to eachother at an angle, of the composed element of FIG. 1;

FIG. 3, at a larger scale, represents a cross-section according to lineof FIG. 1;

FIG. 4, in a front view, schematically represents the first steps of theassembly of the composed element of FIG. 1;

FIG. 5, at a larger scale, represents the portion indicated by F5 inFIG. 4;

FIG. 6 represents the portion indicated by F6 in FIG. 4, such during theinstallation of the upper panel-shaped element;

FIGS. 7 to 24 represent different embodiments of a corner connectionalso according to the present invention;

FIG. 25 represents a particular coupling;

FIG. 26 represents a practical application of the invention;

FIG. 27 represents three panel-shaped elements of a composed elementbeing assembled, similar to that of FIG. 1, however, provided with amasking strip;

FIGS. 28 to 31 represent a number of embodiments for a corner connectionin a composed element.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

FIG. 1 in perspective shows a composed element 1 according to thepresent invention. This relates to a possible embodiment of a composedelement 1, which in this example consists of four panel-shaped elements2 a, 2 b, 2 c and 2 d, which are manufactured of wood-based material. Inthe composed element 1 shown, respectively a mitered corner connectionis applied between the four composing panel-shaped elements 2 a, 2 b, 2c and 2 d. The panel-shaped elements of which the composed element isconstructed, are characterized by the presence of a locking tongue andgroove connection 3 with which the panel-shaped elements can be coupledto each other at an angle and hereby form an outer corner 4 and an innercorner 5, respectively. The composed element 1 thus forms a box, whereinthe panel-shaped elements 2 a, 2 b, 2 c and 2 d form a left-handsidewall, a bottom wall, a right-hand sidewall and an upper wall,respectively.

As represented in FIGS. 2 and 3, each panel-shaped element defines twopanel surfaces 6 a, 7 a and 6 b, 7 b, respectively. Further, eachpanel-shaped element also defines panel edges, in the case of arectangular panel-shaped element four panel edges, which extendtransverse to said panel surfaces. We are talking about an exteriorsurface 6 a, 6 b when a panel surface is situated at the side of aformed outer corner 4 of the corner connection, and we are talking aboutan interior surface 7 a, 7 b when a panel surface is situated at theside of a formed inner corner 4. Mostly, as in FIG. 2, too, the formedinner corner 5 between the panel-shaped elements is a right angle.However, according to the present invention, the formed inner corner 5between the panel-shaped elements possibly may also be an angledifferent from 90°. Possible embodiments hereof will be described below.In most cases, the panel-shaped elements will show an equal panelthickness. However, the corner connection according to the invention canalso be applied with panels of different panel thicknesses. A possibleembodiment thereof will also be described herein below. The tongue 8 andgroove 9 are made in the form of profiled panel edges. As can be seen inFIG. 2, this relates to uninterruptedly continuing profiles of which thetongue 8 and the groove 9 are composed. However, the tongue 8 and/or thegroove 9 can also be made as a discontinuous surface or possibly overonly a part of an edge of the panel-shaped element.

In FIG. 3, for both panel-shaped elements 2 a and 2 b the respectivecenter line is indicated by references Ma and Mb. The center line Ma, Mbof a panel-shaped element 2 a, 2 b, seen in cross-section, indicates themiddle between both panel surfaces 6 a, 6 b and 7 a, 7 b of therespective panel-shaped element. Herein, the two respective panelsurfaces 6 a and 6 b, which are situated at the side of the outer corner4, in coupled condition define a first intersection P1. The tworespective panel surfaces 7 a and 7 b, which are situated at the side ofthe inner corner 5, herein in an analogous manner in coupled conditiondefine a second intersection P2. The aforementioned theoretical miterline L1 is formed between said two intersections P1 and P2. In someembodiments, still according to the present invention, the panelsurfaces of the panel-shaped elements possibly may not continue up tothe respective panel surface of the panel-shaped element to which it iscoupled. In this case, a theoretical inner corner and/or a theoreticalouter corner is determined by the intersection of the respectiveprolongations of the respective panel surfaces, and the theoreticalmiter line L1 is defined by this theoretical inner corner andtheoretical outer corner. The aforementioned theoretical miter line L1is represented in FIG. 3 by means of an axis line.

The theoretical miter angle H1 is defined as the smallest angle whichextends between the theoretical miter line L1 and a perpendicular on thepanel surface 6 a at the height of the outer corner 4 of the respectivepanel-shaped element 2 a and as shown in FIG. 3. In the example of FIG.3, wherein a straight corner connection is shown, said perpendicularcoincides with the center line Mb of the panel-shaped element 2 b havingthe groove 9.

As represented in FIG. 3, said locking tongue and groove connection 3substantially consists of a tongue 8 on one of the aforementionedpanel-shaped elements 2 a and of a groove 9 on another panel-shapedelement 2 b. Further, said locking tongue and groove connection 3 isformed by locking elements 10 and 11 provided on said tongue 8 andgroove 9, which locking elements, in a common mutually coupled conditionof the panel-shaped elements 2 a and 2 b, counteract the drifting apartof tongue 8 and groove 9.

Further, it is shown in this figure that, seen in cross-section, thepanel surface 6 a and 6 b of each panel-shaped element 2 a and 2 b atthe side of the formed outer corner 4 extends up to beyond therespective center line Mb and Ma of the panel-shaped element 2 b and 2 ato which it is coupled. More particularly, in the example of FIG. 3 thetwo panel surfaces 6 a and 6 b, at the side of the outer corner 4, forboth panel-shaped elements 2 a and 2 b, extend right up to this outercorner 4.

In the example of FIG. 3, the tongue 8 is also provided with a slit 12,as a result of which the tongue is divided into a first tongue portion13 and a second tongue portion 14.

Said slit 12 in the tongue 8 can be characterized further by an axisline L2, which, seen in cross-section and in the longitudinal directionof the slit 12 in the tongue 8, globally follows the center of this slit12. Herein below, this axis line L2 is denominated the axis line of theslit L2 and is shown in dashed line in FIG. 3. Hereby, the axis line ofthe slit L2 also represents the direction of the slit in the tongue. Theaxis line of the slit L2 and the theoretical miter line L1 of the mitercoupling also form an intersection, herein below denominated theintersection S2. Herein below, the tongue slit angle H2 is considered asbeing the smallest angle which is enclosed between the axis line of theslit L2 and the center line Ma of the respective panel-shaped element 2a having the tongue 8.

In accordance with the first aspect of the invention, the example fromFIG. 3 shows the characteristic that said slit 12 globally extendsaccording to a direction which deviates from the direction of the centerline Ma of the panel-shaped element 2 a on which the tongue 8 isprovided. More specifically, in the represented example said slit in thetongue 12 is directed inclined towards the inner corner 5 of theintended miter coupling. By a direction directed inclined towards theinner corner 5 must be understood that the axis line of the slit L2extends according to a direction wherein the prolongation of the axisline of the slit L2 beyond the bottom of the slit has an intersectionwith the panel surface 6 a at the side of the formed outer corner 4 andthus does not have an intersection with the panel surface 7 a at theside of the formed inner corner 5.

According to a preferred characteristic of the present invention, thetongue is arranged eccentrically in respect to the intersection S1 ofthe center perpendicular L3 with the theoretical miter line L1, suchpreferably in the direction of said inner corner. For the eccentricityof the tongue, the line portion of the theoretical miter line L1bordered by the tongue 8 is taken into account. In FIG. 3, this lineportion is represented by the line portion P3-P4 and herein below isdenominated the tongue line. The points P3 and P4 are the intersectionsof the contour of the tongue with the theoretical miter line L1. With aneccentric arrangement of the tongue 8, the midpoint T of said tongueline P3-P4 is situated shifted in respect to the intersection S1 of thecenter lines Ma and Mb of the respective panel-shaped elements 2 a and 2b. In FIG. 3, the midpoint of the tongue line P3-P4 is indicated by thepoint T. Preferably, said intersection S1 of the center lines Ma and Mbis situated entirely outward of said tongue line P3-P4. It is noted thatfor embodiments in which the tongue 8 is situated entirely along oneside of the miter line L1, in other words, the tongue 8 itself does nothave any intersections with the theoretical miter line L1, the tongue 8is considered eccentric when the basis of the tongue 8 is eccentric inrespect to the center line Ma of the respective panel-shaped element 2 ahaving the tongue 8.

The example of FIG. 3 also shows the characteristic that said tongue 8is cut free on one side. It is clear that as a result thereof, theembodiment of FIG. 3 also applies said third aspect of the invention.This cutting free of the tongue 8 took place by means of an incision 15,more particularly by means of a narrow incision 15. By cutting thetongue 8 free on at least one side, the tongue 8 or the adjacent tongueportion 13, 14 can be rendered more elastic. More particularly accordingto the first aspect of the invention, the tongue 8 is cut free on onlyone side, here on the side of the tongue 8 which is situated closest tothe formed outer corner 4. Said incision 15 further can be characterizedby an axis line L4, which, seen in cross-section and in the longitudinaldirection of the incision 15, follows the middle of this incision 15.Herein below, this axis line is called the axis line of the incision L4and is shown in dashed line in FIG. 3. Hereby, the axis line of theincision L4 also represents the direction of the incision. Theorientation of the incision now can be characterized by an angle, hereindenominated the incision angle H3, formed between said axis line of theincision L4 and the center line Ma, as represented in FIG. 3.

The example of FIG. 3 shows the characteristic that said lockingelements 10, 11 are only present at the height of one side of the tongue8, as a result of which on the other side of the tongue 8, this latteris free from locking elements. This characteristic allows that thetongue can be turned in the corresponding panel-shaped element withgroove in an advantageous manner.

The example of FIG. 3 also shows the characteristic that said groove 9,seen in cross-section, on the side situated closest to the outer corner4, is bordered by a lip which extends to beyond said theoretical miterline L1, denominated the protruding lip 16. This aspect of the inventionoffers, amongst others, the advantage that a contact surface 17 can beformed between the tongue 8 and the groove 9 beyond the theoreticalmiter line L1. It is clear that hereby, the embodiment of FIG. 3 formsan example of said second aspect of the invention.

The example of FIG. 3 shows the characteristic that said protruding lip16 is located on the side which is situated closest to the formed outercorner 4. In coupled condition, said protruding lip 16 forms two contactsurfaces 17, 18 with the tongue, which provide for a support which iseffective at least according to the direction perpendicular to thecenter line of said panel-shaped element having said tongue. One of saidcontact surfaces 17, 18 is situated beyond the theoretical miter lineL1, on the side of the panel-shaped element 2 a having the tongue 8.

The example of FIG. 3 shows the characteristic that on the side of thegroove 9 which is situated closest to the formed inner corner 5, a smallprotruding lip portion 19 is provided wherein the panel surface 7 b ofthe panel-shaped element having a groove 2 b on the side of the formedinner corner 5, at the height of this inner corner 5, continues tobeyond the theoretical miter line L1, as a result of which a contactsurface 20 is formed there, which coincides with a portion of said panelsurface 7 b.

Preferably, the panel-shaped elements have a covering on one or on bothsides. Such covering may be of any kind and may be realized, forexample, in the form of a laminate, for example, of the HPL type or DPLtype. Other coverings are to be considered, too, such as, for example, afilm, a lacquer layer, which as such may or may not be composed of aplurality of layers. It is noted that in the case of laminate coverings,when manufacturing the panel-shaped elements, preferably from thebeginning it is started from a larger board which already is coated orlaminated on one or both sides, from which board then the smallerpanel-shaped elements will be realized. In FIG. 3, the covering 20 ofthe panel-shaped element is represented schematically. The thickness ofthe shown covering 20 does not necessarily correspond to the realthickness. Rather, the covering here is represented schematically onlyand, for the sake of the clarity of the figure, thicker.

FIG. 4 schematically and in front view shows the construction of thecomposed element of FIG. 1. In this figure, it is shown how the twoupright panel-shaped elements 2 a and 2 c of the composed element can beturned in the lower panel-shaped element 2 b by means of substantially arotation or turning movement, respectively. The respective panel-shapedelements 2 a and 2 c having the tongue, which in the example both haveto be turned in, are inserted from an inclined position andsubsequently, substantially by means of a turning movement R2, areturned in the panel-shaped element having the groove 2 b. Herein, thepanel-shaped element, which is provided inclined, respectively is turnedtowards the final position.

In FIG. 5, at a larger scale a detail of the corner connection isrepresented, as indicated by reference F5 in FIG. 4, wherein the twopanel-shaped elements are not yet completely coupled. In this figure, itis shown that the panel-shaped element 2 a having the tongue can beturned into the corresponding panel-shaped element with groove by meansof a turning movement, possibly in combination with a translationmovement.

In FIG. 6 is shown how, seen in cross-section, the upper panel-shapedelement 2 d of the composed element of FIG. 1, in a last step of theassembly, is coupled to the two upright panel-shaped elements 2 a and 2c. This is performed by placing the groove 9 of the upper panel-shapedelement 2 d on one side, for example, the right-hand side, over thetongue 8 of the right-hand panel-shaped element 2 c and subsequentlyplacing the other groove 9 of the upper panel-shaped element 2 d on theother side, in this example, the left-hand side, over the tongue 8 ofthe left panel-shaped element 2 a. Depending on the chosen embodimentand of the geometry of the tongue 8 and the groove 9, it is possiblethat the already coupled left and/or right panel-shaped elements 2 a, 2c must undergo a very small rotation R1, such that the grooves 9 of theupper panel-shaped element 2 d can be brought on both sides over therespective tongue 8 of the left and right panel-shaped element 2 a and 2c. In FIG. 6, a possible embodiment of this rotation is represented,wherein the panel-shaped element 2 a is brought at an assembly angle H4in respect to the final vertical position, represented here in dottedline. Finally, the upper panel-shaped element 2 d is locked by adownward translation movement V, possibly combined with a rotationalmovement R3. Depending on the chosen embodiment and of the geometry ofthe tongue 8 and groove 9, more or less force has to be exerted duringthis last downward movement V.

In FIGS. 7 to 27, different variants of the locking tongue and grooveconnection according to the present invention are shown.

In FIG. 7, a locking tongue and groove connection 3 is shown accordingto the first aspect of the present invention, wherein the tongue 8 has aslit 12, which, seen in cross-section, globally extends according to adirection which deviates from the direction of the center line Ma of thepanels-shaped element 2 a on which the tongue is provided.

In FIG. 8, a variant of the locking tongue and groove connection 3 isshown, with, in respect to the example of FIG. 7, the additionalpreferred characteristic that the tongue 8 is eccentric in respect tothe intersection S1 of the center perpendicular L3 with said theoreticalmiter line L1. For the eccentricity of the tongue, the line portion ofthe theoretical miter line L1, which is bordered by the tongue 8, istaken into account. In FIG. 8, this tongue is represented by the lineportion P3-P4. With an eccentric arrangement of the tongue 8, themidpoint T of the tongue line is situated shifted in respect to theintersection S1. Preferably, the midpoint S1 of the theoretical miterline is located outward of said tongue line P3-P4.

In FIG. 9, a variant of the locking tongue and groove connection 3 isshown, with, in respect to the example of FIG. 8, the additionalpreferred characteristic that the tongue is cut free on one side. Thiscutting free of the tongue 8 took place by means of an incision 15, moreparticularly by means of a narrow incision 15. By cutting the tongue 8free on at least one side, the tongue 8 or the adjacent tongue portion13, 14 can be rendered more elastic. More particularly also according tothe first aspect of the invention, the tongue 8 is cut free at one sideonly, here at the side of the tongue portion 13 which is situatedclosest to the formed outer corner 4. The incision 15 further ischaracterized by an incision angle H3, as represented in FIG. 9.

In FIG. 10, a variant of the locking tongue and groove connection isshown, with, in respect to the example of FIG. 9, the additionalpreferred characteristic that the groove is bordered on one side by alip 16 which extends to beyond said miter line. This lip is denominatedthe protruding lip 16. This second aspect of the invention offers theadvantage that a contact surface 17 between the tongue 8 and the groove9 can be formed beyond the theoretical miter line L1.

In FIG. 11, a variant of the locking tongue and groove connection isshown, with, in respect to the example of FIG. 10, the additionalpreferred characteristic that the panel surface 7 b of the panel-shapedelement 2 b having the groove at the side of the formed inner corner 5,continues at the height of this inner corner 5 beyond the theoreticalmiter line L1, as a result of which at that location a contact surface21 is formed, which coincides with a portion of said panel surface 7 b.

In FIG. 12, a locking tongue and groove connection 3 is shown, accordingto the second aspect of the present invention, wherein the groove 9 atone side is bordered by a lip 16 which extends to beyond the theoreticalmiter line, also denominated protruding lip 16.

In FIG. 13, a variant of the locking tongue and groove connection 3 isshown, with, in respect to the example of FIG. 12, the additionalpreferred characteristic that the tongue has a slit 12, which, seen incross-section, globally extends according to a direction which deviatesfrom the direction of the center line Ma of the panel-shaped element 2 aon which the tongue is provided.

In FIG. 14, a variant of the locking tongue and groove connection 3 isshown, with, in respect to the example of FIG. 12, the additionalpreferred characteristic that the tongue is cut free at one side. Thiscutting free of the tongue 8 took place by means of an incision 15, moreparticularly by means of a narrow incision 15. More particularly alsoaccording to the third aspect of the invention, the tongue 8 is cut freeat one side only, here at the side of the tongue 4 which is situatedclosest to the formed outer corner 4.

In FIG. 15, an example is shown, wherein, as represented schematically,particle board is used, which comprises a basic layer with coarserparticles, in other words, relatively coarse chips, and which, at leaston one of the sides thereof, and in this case on both sides thereof, hasan outer layer 22 with particles, which in respect to average finenesshave a higher degree of fineness than the particles of said basic layer.The separation between the outer layer 22 with high density and thebasic layer of the panel-shaped element is indicated in FIG. 15 by aseparation line L5 in dash-dotted line. As a particular characteristic,herein the whole is configured such that the locking surface of at leastone of the locking elements 10-11, and in this case the locking surfacesof both locking elements, is, are, respectively, situated at leastpartially in the outer layer 22 or at least in the immediate proximitythereof. More particularly, in the example of FIG. 15, the lockingsurface of the locking element 10 is situated entirely in the respectiveouter layer 22 of the respective panel-shaped element 2 a, whereas thelocking surface of the locking element 11 is situated at a smalldistance from the respective outer layer 22 of the respectivepanel-shaped element 2 b. Said small distance preferably is no largerthan 2 millimeters. In other words, this means in the example that thedistance between the locking surface of the locking element 11 to theclosely situated separation line L5 of the panel-shaped element 2 b isnot more than 2 millimeters. By situating such locking surface in suchfiner outer layer 22, the advantage is obtained that such lockingsurface is located in the most compact and stable layer, which finallywill be beneficial for the strength of the coupling. Moreover, also theadvantage is obtained that smoother surfaces can be created in thisouter layer, which is of importance for achieving a good couplingfunction. When such locking surface is situated at a small distance fromthe outer layer 22, however, the last-mentioned advantage is no longerachieved, but the closely situated outer layer 22 still provides for astrong locking element 11, as then still a sufficient support of thematerial of the basic layer will be provided.

It is noted that such configuration of one or more locking surfaces inrespect to one or more of such outer layers can also be applied in allembodiments of the first, second and/or third aspect of the invention.FIG. 15 in fact represents an embodiment in which the first as well asthe second and third aspect are combined.

In FIG. 15, as a particular characteristic it is also illustrated thatthe slit 12 is performed up to a large depth.

In FIG. 16, a locking tongue and groove connection 3 is shown, accordingto the first, second and third aspect of the present invention, whereinthe tongue 8 consists of a split tongue and wherein the tongue is cutfree at one side. Further, the represented example shows thecharacteristic that the orientation of the tongue slit and of theincision differs from the orientation of examples shown before. Thisillustrates the degrees of freedom which are obtained for freelychoosing the orientation of the slit and the orientation of the incisionand adapting them to the desired application.

In FIG. 17, a locking tongue and groove connection 3 is shown, accordingto the first, second and third aspect of the present invention, whereinthe miter coupling shows an open outer corner 4. In this embodiment,still according to the present invention, the panel surfaces 6 a and 6 bof the panel-shaped elements 2 a and 2 b do not continue up to therespective panel surface of the panel-shaped element to which it iscoupled. In this case, a theoretical outer corner 4 is determined by theintersection of the respective prolongations of the respective panelsurfaces 6 a and 6 b, and the theoretical miter line L1 is defined bythe inner corner 5 and theoretical outer corner 4. The open outer corner4 can possibly be finished by means of a masking strip 23, such as, forexample, a laminate strip or a masking strip 23 of synthetic material,for example, an ABS strip.

In FIG. 18, a locking tongue and groove connection 3 is shown, accordingto the first, second and third aspect of the present invention, whereinthe miter coupling shows an open outer corner and wherein it comprises aseparate corner element 24. It is noted that the example shown shows acovering 20 at one side of the panel-shaped elements. Of course, thecovering may also be present on both sides of the panel-shaped elements.

In FIG. 19, a panel-shaped element 2 a with tongue of a locking tongueand groove connection 3 is shown, according to the first, second andthird aspect of the present invention, wherein the tongue slit 12 andthe incision 15 are filled with an elastically deformable material 25.

In FIG. 20, a locking tongue and groove connection 3 is shown, accordingto the first, second and third aspect of the present invention, whereinthe orientation of the tongue slit and the orientation of the incisionare different. In other words, in this embodiment the tongue slit angleH2 and the incision angle H3 are different. Further, in this figure anexample is given of a possible embodiment in which use is made of acontact surface 17 formed by an insert 26 provided in the edge. Morespecifically, the shown insert 26 consists of a strip which is providedwith a movable portion 27 with contact surface 17, which cooperates withthe tongue 8 on the other panel-shaped element 2 a. According to a notrepresented example, the locking element 11, too, can be formed by aninsert, whether or not in combination with the insert 26.

FIG. 21 shows a possible embodiment, wherein the panel surface 6 a ofthe panel-shaped element having the tongue, which is situated at theside of the formed outer corner, does not continue up to the formedouter corner 4, but up to a certain distance X therefrom. However, thisdistance X is smaller than half of the panel thickness Wb of thepanel-shaped element with groove 2 b to which it is coupled.

FIG. 22 shows a possible embodiment, wherein the panel-shaped elements,which are coupled to each other at an angle, have a different panelthickness. In this case, this is also called a non-perpendicular miterjoint. The lower panel-shaped element 2 b has a panel thickness Wb whichis smaller than the panel thickness Wa of the left-hand panel-shapedelement 2 a to which it is coupled. It is noted that the miter angle H1can be expressed as H1=arc tan (Wb/Wa).

FIGS. 23 and 24 show possible embodiments, wherein the panel-shapedelements 2 a and 2 b are coupled to each other at an angle which isdifferent from 90°. It is noted that in this case the miter angle H1 isdifferent from 45°, as it is the case in the embodiments shown earlier.In FIG. 23, an example is shown wherein the formed angle measured at theinner corner is larger than 90°. In FIG. 24, an example is shown whereinthe formed angle measured at the inner corner is smaller than 90°.

From the represented corner connections of the invention, shapes canalso be derived which are suitable for forming a T-connection. Anexample thereof is represented in FIG. 25.

FIG. 26 also shows a practical application of the invention, moreparticularly a table 1, wherein a base is composed of four panel-shapedelements 2 a, 2 b, 2 c and 2 d, which are connected to each other at anangle by means of mitered corner connection 3 according to theinvention.

FIG. 27 shows three panel-shaped elements 2 a, 2 b and 2 c, inconstruction as from a similar composed element such as of FIG. 1,however, wherein the panel-shaped elements 2 a, 2 b and 2 c, on edgeswhere no tongue 8 or groove are present, are finished with a maskingstrip 28, which is miter-joined with the masking strip 28 of therespective other panel-shaped elements.

FIG. 28 shows an embodiment which is realized, amongst others, accordingto the fourth aspect of the invention. Herein, this thus relates to acomposed element, which comprises at least two panel-shaped elements 2a-2 b, each with respective panel surfaces, wherein for eachpanel-shaped element a center line Ma-Mb is defined centrally betweenthe two panel surfaces of that panel-shaped element;

-   -   wherein said panel-shaped elements preferably are manufactured        of wood-based material;    -   wherein said panel-shaped elements can be coupled to each other        at an angle of 90 degrees or approximately 90 degrees by means        of a locking tongue and groove connection and herein        respectively form an inner and outer corner, wherein the inner        and outer corner define a theoretical miter line L1;    -   wherein said locking tongue and groove connection substantially        is formed of a tongue 8 on one of said panel-shaped elements, of        a groove 9 on another of said panel-shaped elements and of        locking elements 10-11 provided on said tongue and groove,        respectively;    -   wherein, seen in cross-section, the panel surface of each        panel-shaped element at the side of the formed outer corner        extends at least up to the center line of the panel-shaped        element to which it is coupled; and    -   wherein the tongue preferably consists of a split tongue, with        thus at least a first tongue portion and a second tongue        portion, as well as a slit 12 situated there between;        further with the characteristic that said tongue 8, at the        location of the theoretical miter line L1, is located entirely        outward of the midpoint S1 of the theoretical miter line L1,        such between the midpoint S1 and the inner corner.

FIG. 29 shows another particular variant of the first aspect of theinvention. Herein, this relates to a composed element, wherein thetongue 8 consists of a split tongue, wherein the slit 12, globally seenand/or with the wall thereof which is situated closest to the innercorner, from the free end, in other words, open end thereof extendstowards the bottom inclined towards the panel surface which is locatedat the inner corner 5, such as is clearly visible here by means of theinclined axis line L2. Hereby, the flexibility of the tongue portionwhich comprises the locking element 10 can be adjusted in an easy mannerby letting the slit end closer or less close to the respective panelsurface.

FIG. 30 represents a particular embodiment of the second aspect of theinvention. Herein, the groove 9, at least at one side thereof, seen incross-section, is bordered by a lip 16 which is located at least with aportion 29 thereof beyond said theoretical miter line L1, and this lip16, in coupled condition, is located at the side of the tongue 8 whichis situated closest to the formed outer corner 4, and this in such amanner that the aforementioned portion 29 provides at least a contactsurface 17 for the tongue 8. Hereby, a good lateral support is offeredfor the tongue.

A further particularity herein consists in that the lip 16 has a distalend 30, which extends up to the plane of the panel-shaped element 2 b inwhich the groove 8 is provided and which is situated at the inner cornerand preferably is formed by a portion of the inner wall of thepanel-shaped element. In other words, this means that the end 30 isformed by a portion of the panel surface 7 b. Hereby, it is obtainedthat the groove 9 can be provided in the flat panel surface 7 b in asimple manner.

Another particularity, which may or may not be applied in combinationwith the particularity described immediately herein above, consists inthat the panel-shaped element which is provided with the tongue has aprotruding edge portion 31, which on the outer side provides for aprolongation of the panel surface and on the inner side is situatedopposite to said portion 29 of the lip 16 and preferably adjoiningthereto, wherein this protruding edge portion 31 extends at least up tothe center line Mb of the panel-shaped element which comprises thegroove 9, and preferably up to the corner point or approximately up tothe corner point of the actual outer corner. Hereby, a miter coupling isobtained with a connection near the corner point, whereas the tongue 8as such, globally seen, can be realized approximately perpendicular tothe panel-shaped element having the groove.

According to a particular characteristic, the protruding edge portion31, next to its distal end 32, comprises a locking part 33, which, incoupled condition, engages behind the other panel-shaped element 2 b, insuch a manner that the relatively thin edge portion 31 is prevented frombending out due to warping.

FIGS. 30 and 31 commonly illustrate the fifth aspect of the invention.Both figures are represented at the same scale. The panel thickness ofthe panel-shaped elements of FIG. 30 is smaller than the panel thicknessof the panel-shaped elements of FIG. 31. The tongue and groove profileswhich are situated in the zone G1, however, are identical to each otherin respect to shape as well as to size. Adaptation takes place outsideof the zones G1, thus in zone G2 or G3. In the example, this is in zoneG3, by adapting the thickness of the edge portion 31 in function of thepanel thickness.

However, this latter does not exclude to apply identical profiles alsooutside of the zone G1. In the represented example, the zones G2 and G3are made identical to each other as well, with the only difference thatthe portion being at 45 degrees, which is situated on the outer corner4, extends somewhat longer. It is clear that then the same cutting toolsand tool settings can be applied for the entire edge finishing.

In FIGS. 30 and 31 also a particularity is represented, which consistsin that the panel-shaped element 2 a can be fixedly snapped into thepanel-shaped element 2 b by means of a movement perpendicular orapproximately perpendicular to this latter, such by means of aninclination 34, which can shift along the locking element 11.

According to a general preferred characteristic, the tongue and grooveconnection is made such that the panel-shaped elements can be connectedto each other by means of a snap movement as well as by means of aturning movement.

It is noted that the herein above-described panel-shaped elementsaccording to the invention can be composed in different manners.According to a first possibility, for such panel-shaped element awood-based single board is applied, which is manufactured of one and thesame or substantially the same material, for example, a single MDF board(Medium Density Fiberboard) or HDF board (High Density Fiberboard), or aclassic particle board, possibly with finer wood particles on theexterior surfaces. By a single board is meant that only one substantialstructural material layer is applied, which does not exclude that otherthin layers, such as coverings, can be present. Alternatively, thepanel-shaped elements will consist of a multi-layered board, such as,for example, plywood boards.

Further, it is also noted that the invention is in no way limited tocubical composed elements, but that also complete pieces of furniture,possibly with a plurality of compartments or partitions, possiblyprovided with shelves, drawers, doors and the like, can be provided witha respective corner connection according to the invention.

By a “composed element”, according to the invention an element has to beunderstood which is already assembled, as well as such element whichstill is in disassembled condition. More particularly, this means that apiece of RTA furniture, which meets the invention and still is indisassembled condition, for example, packaged as a flat-pack piece offurniture, in this condition also has to be considered a “composedelement”.

It is clear that the invention primarily relates to furniture andfurniture parts. It also relates to panel-shaped elements which compriseone or more coupling parts with which a corner connection according tothe invention can be realized.

Finally, it is also noted that said panel-shaped elements mostly areelements which cover an entire or large portion of a wall of thecomposed elements of which it is a part. However, in some applications,such as, for example, basic elements of a piece of kitchen furniture,more particularly, for example, the basic elements of floor units, thepanel-shaped element can be provided at the height of one or more wallsof the composed element as a smaller component, such as a slat. In theexample of the piece of kitchen furniture, the slat typically serves asa support surface for an additional panel-shaped element, such as, forexample, a worktop.

The present invention is in no way limited to the embodiments describedherein above; on the contrary, such composed elements and the respectivecorner connection can be realized according to various forms anddimensions, without leaving the scope of the present invention.

1. Composed element, which comprises at least two panel-shaped elements,each with respective panel surfaces wherein for each panel-shapedelement a center line is defined centrally between the two panelsurfaces of that panel-shaped element; wherein said panel-shapedelements can be coupled to each other at an angle by means of a lockingtongue and groove connection and thereby respectively from an innercorner and outer corner, wherein the inner corner and outer cornerdefine a theoretical miter line; wherein said locking tongue and grooveconnection respectively is substantially formed of a tongue on one ofsaid panel-shaped elements, of a groove on another of said panel-shapedelements, and of locking elements provided on said tongue and groove;wherein, seen in cross-section, the panel surface of each panel-shapedelement at the side of the formed outer corner extends up to a distanceform said outer corner which is smaller than three quarters of the panelthickness of the panel-shaped element to which it is coupled.
 2. Thecomposed element of claim 1, wherein the panel surface of eachpanel-shaped element at the side of the formed outer corner extends atleast up to the center line of the panel-shaped element to which it iscoupled.
 3. The composed element of claim 1, wherein the panel surfaceof each panel-shaped element at the side of the formed outer cornerextends up to a distance from said outer corner, wherein said distanceis smaller than one quarter of the panel-shaped element to which it iscoupled.
 4. The composed element of claim 1, wherein said outer corneris finished by means of a masking strip.
 5. The composed element ofclaim 4, wherein said masking strip is chosen from the list consistingof a laminate strip and an ABS strip.
 6. The composed element of claim1, wherein said outer corner comprises a separate corner element.
 7. Thecomposed element of claim 1 or 2, wherein the panel surface at the sideof the outer corner of the panel shaped element having the tonguecontinues up to a distance from said outer corner, wherein said distanceis smaller than half of the panel thickness of the panel-shaped elementwith the groove to which it is coupled.
 8. The composed element of claim1, wherein said panel-shaped elements (2 a, 2 b), in respect to thematerial from which they are manufactured, show one or more of saidcharacteristics: the panel-shaped elements substantially consist of abasic board formed of solid wood; the panel-shaped elementssubstantially consist of a basic board formed of a wood-based pressedboard; the panel-shaped elements substantially consist of a basic boardformed of wood fibers, more particularly MDF or HDF; the panel-shapedelements substantially consist of a basic board formed of particleboard; the panel-shaped elements are formed of multi-layered and/ormulti-part board; the panel-shaped elements are formed of melaminatedboard; the panel-shaped elements comprise a lightweight board, possiblywith edges from another material; the panel-shaped elements areconstructed as a hollow board or as a board provided with cavities, forexample, with a honeycomb core, possibly with edges from anothermaterial; the panel-shaped elements are constructed of a basic boardwith a covering, more particularly a covering of synthetic material ortextile.
 9. The composed element of claim 1, wherein said locking tongueand groove connection comprises a contact surface formed by an insert,wherein said insert is provided in an edge of one of the panel-shapedelements.
 10. The composed element of claim 1, wherein said lockingtongue and groove connection comprises a locking element formed by aninsert, wherein said insert is provided in an edge of one of thepanel-shaped elements.
 11. The composed element of claim 9 or 10,wherein said insert consists of a strip which is movable and cooperateswith said tongue or groove.